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/*
 * @(#)ByteArrayImageInputStream.java  1.0  2008-10-18
 *
 * Copyright (c) 2008 Werner Randelshofer, Immensee, Switzerland.
 * All rights reserved.
 *
 * You may not use, copy or modify this file, except in compliance with the
 * license agreement you entered into with Werner Randelshofer.
 * For details see accompanying license terms.
 */
package ch.randelshofer.io;

import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteOrder;
import java.util.Stack;
import javax.imageio.stream.IIOByteBuffer;
import javax.imageio.stream.ImageInputStream;

/**
 * ByteArrayImageInputStream.
 *
 * @author Werner Randelshofer, Hausmatt 10, CH-6405 Immensee
 * @version 1.0 2008-10-18 Created.
 */
public class ByteArrayImageInputStream extends ByteArrayInputStream implements ImageInputStream {

    /**
     * The byte order of the stream as an instance of the enumeration
     * class java.nio.ByteOrder, where
     * ByteOrder.BIG_ENDIAN indicates network byte order
     * and ByteOrder.LITTLE_ENDIAN indicates the reverse
     * order.  By default, the value is
     * ByteOrder.BIG_ENDIAN.
     */
    protected ByteOrder byteOrder = ByteOrder.BIG_ENDIAN;
    /**
     * The current bit offset within the stream.  Subclasses are
     * responsible for keeping this value current from any method they
     * override that alters the bit offset.
     */
    protected int bitOffset;
    /** Length of the buffer used for readFully(type[], int, int) */
    private static final int BYTE_BUF_LENGTH = 8192;
    /** Byte buffer used for readFully(type[], int, int) */
    private byte[] byteBuf = new byte[BYTE_BUF_LENGTH];
    /** The last flushed positione. */
    private long flushedPos;

    private static class Marker {
        private int bytePos, bitPos;
        public Marker(int bytePos, int bitPos) {
            this.bytePos=bytePos;
            this.bitPos=bitPos;
        }
    };

    /** Marked bit and byte positions. */
    private Stack markStack = new Stack();
    /** The offset of the input stream in the underlying byte array. */
    private int arrayOffset;

    public ByteArrayImageInputStream(byte[] buf) {
        this(buf, ByteOrder.BIG_ENDIAN);
    }

    public ByteArrayImageInputStream(byte[] buf, ByteOrder byteOrder) {
        this(buf, 0, buf.length, byteOrder);
    }

    public ByteArrayImageInputStream(byte[] buf, int offset, int length, ByteOrder byteOrder) {
        super(buf, offset, length);
        arrayOffset = offset;
        this.byteOrder = byteOrder;
    }

//    @Override
    public void setByteOrder(ByteOrder byteOrder) {
        this.byteOrder = byteOrder;
    }

//    @Override
    public ByteOrder getByteOrder() {
        return byteOrder;
    }

//    @Override
    public void readBytes(IIOByteBuffer buf, int len) throws IOException {
        if (len < 0) {
            throw new IndexOutOfBoundsException("len < 0!");
        }
        if (buf == null) {
            throw new NullPointerException("buf == null!");
        }

        byte[] data = new byte[len];
        len = read(data, 0, len);

        buf.setData(data);
        buf.setOffset(0);
        buf.setLength(len);
    }

//    @Override
    public boolean readBoolean() throws IOException {
        int ch = this.read();
        if (ch < 0) {
            throw new EOFException();
        }
        return (ch != 0);
    }

//    @Override
    public byte readByte() throws IOException {
        int ch = this.read();
        if (ch < 0) {
            throw new EOFException();
        }
        return (byte) ch;
    }

//    @Override
    public int readUnsignedByte() throws IOException {
        int ch = this.read();
        if (ch < 0) {
            throw new EOFException();
        }
        return ch;
    }

//    @Override
    public short readShort() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        if ((ch1 | ch2) < 0) {
            throw new EOFException();
        }

        if (byteOrder == ByteOrder.BIG_ENDIAN) {
            return (short) ((ch1 << 8) + (ch2 << 0));
        } else {
            return (short) ((ch2 << 8) + (ch1 << 0));
        }
    }

//    @Override
    public int readUnsignedShort() throws IOException {
        return (readShort()) & 0xffff;
    }

//    @Override
    public char readChar() throws IOException {
        return (char) readShort();
    }

//    @Override
    public int readInt() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        int ch3 = this.read();
        int ch4 = this.read();
        if ((ch1 | ch2 | ch3 | ch4) < 0) {
            throw new EOFException();
        }

        if (byteOrder == ByteOrder.BIG_ENDIAN) {
            return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
        } else {
            return ((ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0));
        }
    }

//    @Override
    public long readUnsignedInt() throws IOException {
        return (readInt()) & 0xffffffffL;
    }

//    @Override
    public long readLong() throws IOException {
        int i1 = readInt();
        int i2 = readInt();

        if (byteOrder == ByteOrder.BIG_ENDIAN) {
            return ((long) i1 << 32) + (i2 & 0xFFFFFFFFL);
        } else {
            return ((long) i2 << 32) + (i1 & 0xFFFFFFFFL);
        }
    }

//    @Override
    public float readFloat() throws IOException {
        return Float.intBitsToFloat(readInt());
    }

//    @Override
    public double readDouble() throws IOException {
        return Double.longBitsToDouble(readLong());
    }

//    @Override
    public String readLine() throws IOException {
        StringBuffer input = new StringBuffer();
        int c = -1;
        boolean eol = false;

        while (!eol) {
            switch (c = read()) {
                case -1:
                case '\n':
                    eol = true;
                    break;
                case '\r':
                    eol = true;
                    long cur = getStreamPosition();
                    if ((read()) != '\n') {
                        seek(cur);
                    }
                    break;
                default:
                    input.append((char) c);
                    break;
            }
        }

        if ((c == -1) && (input.length() == 0)) {
            return null;
        }
        return input.toString();
    }

//    @Override
    public String readUTF() throws IOException {
        this.bitOffset = 0;

        // Fix 4494369: method ImageInputStreamImpl.readUTF()
        // does not work as specified (it should always assume
        // network byte order).
        ByteOrder oldByteOrder = getByteOrder();
        setByteOrder(ByteOrder.BIG_ENDIAN);

        String ret;
        try {
            ret = DataInputStream.readUTF(this);
        } catch (IOException e) {
            // Restore the old byte order even if an exception occurs
            setByteOrder(oldByteOrder);
            throw e;
        }

        setByteOrder(oldByteOrder);
        return ret;
    }

//    @Override
    public void readFully(byte[] b, int off, int len) throws IOException {
        // Fix 4430357 - if off + len < 0, overflow occurred
        if (off < 0 || len < 0 || off + len > b.length || off + len < 0) {
            throw new IndexOutOfBoundsException("off < 0 || len < 0 || off + len > b.length!");
        }

        while (len > 0) {
            int nbytes = read(b, off, len);
            if (nbytes == -1) {
                throw new EOFException();
            }
            off += nbytes;
            len -= nbytes;
        }
    }

//    @Override
    public void readFully(byte[] b) throws IOException {
        readFully(b, 0, b.length);
    }

//    @Override
    public void readFully(short[] s, int off, int len) throws IOException {
        // Fix 4430357 - if off + len < 0, overflow occurred
        if (off < 0 || len < 0 || off + len > s.length || off + len < 0) {
            throw new IndexOutOfBoundsException("off < 0 || len < 0 || off + len > s.length!");
        }

        while (len > 0) {
            int nelts = Math.min(len, byteBuf.length / 2);
            readFully(byteBuf, 0, nelts * 2);
            toShorts(byteBuf, s, off, nelts);
            off += nelts;
            len -= nelts;
        }
    }

//    @Override
    public void readFully(char[] c, int off, int len) throws IOException {
        // Fix 4430357 - if off + len < 0, overflow occurred
        if (off < 0 || len < 0 || off + len > c.length || off + len < 0) {
            throw new IndexOutOfBoundsException("off < 0 || len < 0 || off + len > c.length!");
        }

        while (len > 0) {
            int nelts = Math.min(len, byteBuf.length / 2);
            readFully(byteBuf, 0, nelts * 2);
            toChars(byteBuf, c, off, nelts);
            off += nelts;
            len -= nelts;
        }
    }

//    @Override
    public void readFully(int[] i, int off, int len) throws IOException {
        // Fix 4430357 - if off + len < 0, overflow occurred
        if (off < 0 || len < 0 || off + len > i.length || off + len < 0) {
            throw new IndexOutOfBoundsException("off < 0 || len < 0 || off + len > i.length!");
        }

        while (len > 0) {
            int nelts = Math.min(len, byteBuf.length / 4);
            readFully(byteBuf, 0, nelts * 4);
            toInts(byteBuf, i, off, nelts);
            off += nelts;
            len -= nelts;
        }
    }

//    @Override
    public void readFully(long[] l, int off, int len) throws IOException {
        // Fix 4430357 - if off + len < 0, overflow occurred
        if (off < 0 || len < 0 || off + len > l.length || off + len < 0) {
            throw new IndexOutOfBoundsException("off < 0 || len < 0 || off + len > l.length!");
        }

        while (len > 0) {
            int nelts = Math.min(len, byteBuf.length / 8);
            readFully(byteBuf, 0, nelts * 8);
            toLongs(byteBuf, l, off, nelts);
            off += nelts;
            len -= nelts;
        }
    }

//    @Override
    public void readFully(float[] f, int off, int len) throws IOException {
        // Fix 4430357 - if off + len < 0, overflow occurred
        if (off < 0 || len < 0 || off + len > f.length || off + len < 0) {
            throw new IndexOutOfBoundsException("off < 0 || len < 0 || off + len > f.length!");
        }

        while (len > 0) {
            int nelts = Math.min(len, byteBuf.length / 4);
            readFully(byteBuf, 0, nelts * 4);
            toFloats(byteBuf, f, off, nelts);
            off += nelts;
            len -= nelts;
        }
    }

//    @Override
    public void readFully(double[] d, int off, int len) throws IOException {
        // Fix 4430357 - if off + len < 0, overflow occurred
        if (off < 0 || len < 0 || off + len > d.length || off + len < 0) {
            throw new IndexOutOfBoundsException("off < 0 || len < 0 || off + len > d.length!");
        }

        while (len > 0) {
            int nelts = Math.min(len, byteBuf.length / 8);
            readFully(byteBuf, 0, nelts * 8);
            toDoubles(byteBuf, d, off, nelts);
            off += nelts;
            len -= nelts;
        }
    }

    private void toShorts(byte[] b, short[] s, int off, int len) {
        int boff = 0;
        if (byteOrder == ByteOrder.BIG_ENDIAN) {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff];
                int b1 = b[boff + 1] & 0xff;
                s[off + j] = (short) ((b0 << 8) | b1);
                boff += 2;
            }
        } else {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff + 1];
                int b1 = b[boff] & 0xff;
                s[off + j] = (short) ((b0 << 8) | b1);
                boff += 2;
            }
        }
    }

    private void toChars(byte[] b, char[] c, int off, int len) {
        int boff = 0;
        if (byteOrder == ByteOrder.BIG_ENDIAN) {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff];
                int b1 = b[boff + 1] & 0xff;
                c[off + j] = (char) ((b0 << 8) | b1);
                boff += 2;
            }
        } else {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff + 1];
                int b1 = b[boff] & 0xff;
                c[off + j] = (char) ((b0 << 8) | b1);
                boff += 2;
            }
        }
    }

    private void toInts(byte[] b, int[] i, int off, int len) {
        int boff = 0;
        if (byteOrder == ByteOrder.BIG_ENDIAN) {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff];
                int b1 = b[boff + 1] & 0xff;
                int b2 = b[boff + 2] & 0xff;
                int b3 = b[boff + 3] & 0xff;
                i[off + j] = (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;
                boff += 4;
            }
        } else {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff + 3];
                int b1 = b[boff + 2] & 0xff;
                int b2 = b[boff + 1] & 0xff;
                int b3 = b[boff] & 0xff;
                i[off + j] = (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;
                boff += 4;
            }
        }
    }

    private void toLongs(byte[] b, long[] l, int off, int len) {
        int boff = 0;
        if (byteOrder == ByteOrder.BIG_ENDIAN) {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff];
                int b1 = b[boff + 1] & 0xff;
                int b2 = b[boff + 2] & 0xff;
                int b3 = b[boff + 3] & 0xff;
                int b4 = b[boff + 4];
                int b5 = b[boff + 5] & 0xff;
                int b6 = b[boff + 6] & 0xff;
                int b7 = b[boff + 7] & 0xff;

                int i0 = (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;
                int i1 = (b4 << 24) | (b5 << 16) | (b6 << 8) | b7;

                l[off + j] = ((long) i0 << 32) | (i1 & 0xffffffffL);
                boff += 8;
            }
        } else {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff + 7];
                int b1 = b[boff + 6] & 0xff;
                int b2 = b[boff + 5] & 0xff;
                int b3 = b[boff + 4] & 0xff;
                int b4 = b[boff + 3];
                int b5 = b[boff + 2] & 0xff;
                int b6 = b[boff + 1] & 0xff;
                int b7 = b[boff] & 0xff;

                int i0 = (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;
                int i1 = (b4 << 24) | (b5 << 16) | (b6 << 8) | b7;

                l[off + j] = ((long) i0 << 32) | (i1 & 0xffffffffL);
                boff += 8;
            }
        }
    }

    private void toFloats(byte[] b, float[] f, int off, int len) {
        int boff = 0;
        if (byteOrder == ByteOrder.BIG_ENDIAN) {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff];
                int b1 = b[boff + 1] & 0xff;
                int b2 = b[boff + 2] & 0xff;
                int b3 = b[boff + 3] & 0xff;
                int i = (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;
                f[off + j] = Float.intBitsToFloat(i);
                boff += 4;
            }
        } else {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff + 3];
                int b1 = b[boff + 2] & 0xff;
                int b2 = b[boff + 1] & 0xff;
                int b3 = b[boff + 0] & 0xff;
                int i = (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;
                f[off + j] = Float.intBitsToFloat(i);
                boff += 4;
            }
        }
    }

    private void toDoubles(byte[] b, double[] d, int off, int len) {
        int boff = 0;
        if (byteOrder == ByteOrder.BIG_ENDIAN) {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff];
                int b1 = b[boff + 1] & 0xff;
                int b2 = b[boff + 2] & 0xff;
                int b3 = b[boff + 3] & 0xff;
                int b4 = b[boff + 4];
                int b5 = b[boff + 5] & 0xff;
                int b6 = b[boff + 6] & 0xff;
                int b7 = b[boff + 7] & 0xff;

                int i0 = (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;
                int i1 = (b4 << 24) | (b5 << 16) | (b6 << 8) | b7;
                long l = ((long) i0 << 32) | (i1 & 0xffffffffL);

                d[off + j] = Double.longBitsToDouble(l);
                boff += 8;
            }
        } else {
            for (int j = 0; j < len; j++) {
                int b0 = b[boff + 7];
                int b1 = b[boff + 6] & 0xff;
                int b2 = b[boff + 5] & 0xff;
                int b3 = b[boff + 4] & 0xff;
                int b4 = b[boff + 3];
                int b5 = b[boff + 2] & 0xff;
                int b6 = b[boff + 1] & 0xff;
                int b7 = b[boff] & 0xff;

                int i0 = (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;
                int i1 = (b4 << 24) | (b5 << 16) | (b6 << 8) | b7;
                long l = ((long) i0 << 32) | (i1 & 0xffffffffL);

                d[off + j] = Double.longBitsToDouble(l);
                boff += 8;
            }
        }
    }

//    @Override
    public long getStreamPosition() {
        checkClosed();
        return pos - arrayOffset;
    }

//    @Override
    public int getBitOffset() {
        checkClosed();
        return bitOffset;
    }

//    @Override
    public void setBitOffset(int bitOffset) {
        checkClosed();
        if (bitOffset < 0 || bitOffset > 7) {
            throw new IllegalArgumentException("bitOffset must be betwwen 0 and 7!");
        }
        this.bitOffset = bitOffset;
    }

//    @Override
    public int readBit() throws IOException {
        checkClosed();

        // Compute final bit offset before we call read() and seek()
        int newBitOffset = (this.bitOffset + 1) & 0x7;

        int val = read();
        if (val == -1) {
            throw new EOFException();
        }

        if (newBitOffset != 0) {
            // Move byte position back if in the middle of a byte
            seek(getStreamPosition() - 1);
            // Shift the bit to be read to the rightmost position
            val >>= 8 - newBitOffset;
        }
        this.bitOffset = newBitOffset;

        return val & 0x1;
    }

//    @Override
    public long readBits(int numBits) throws IOException {
        checkClosed();

        if (numBits < 0 || numBits > 64) {
            throw new IllegalArgumentException();
        }
        if (numBits == 0) {
            return 0L;
        }

        // Have to read additional bits on the left equal to the bit offset
        int bitsToRead = numBits + bitOffset;

        // Compute final bit offset before we call read() and seek()
        int newBitOffset = (this.bitOffset + numBits) & 0x7;

        // Read a byte at a time, accumulate
        long accum = 0L;
        while (bitsToRead > 0) {
            int val = read();
            if (val == -1) {
                throw new EOFException();
            }

            accum <<= 8;
            accum |= val;
            bitsToRead -= 8;
        }

        // Move byte position back if in the middle of a byte
        if (newBitOffset != 0) {
            seek(getStreamPosition() - 1);
        }
        this.bitOffset = newBitOffset;

        // Shift away unwanted bits on the right.
        accum >>>= (-bitsToRead); // Negative of bitsToRead == extra bits read

        // Mask out unwanted bits on the left
        accum &= (-1L >>> (64 - numBits));

        return accum;
    }

//    @Override
    public long length() throws IOException {
        return count;
    }

//    @Override
    public int skipBytes(int n) throws IOException {
        long pos = getStreamPosition();
        seek(pos + n);
        return (int) (getStreamPosition() - pos);
    }

//    @Override
    public long skipBytes(long n) throws IOException {
        long pos = getStreamPosition();
        seek(pos + n);
        return (int) (getStreamPosition() - pos);
    }

//    @Override
    public void seek(long pos) throws IOException {
        if (pos < 0) {
            throw new IndexOutOfBoundsException("pos < 0!");
        }

        this.pos = (int) pos + arrayOffset;
        this.bitOffset = 0;
    }

//    @Override
    public void flushBefore(long pos) throws IOException {
        if (pos < flushedPos) {
            throw new IndexOutOfBoundsException("pos < flushedPos!");
        }
        if (pos > getStreamPosition()) {
            throw new IndexOutOfBoundsException("pos > getStreamPosition()!");
        }
        // Invariant: flushedPos >= 0
        flushedPos = pos + arrayOffset;
    }

//    @Override
    public void flush() throws IOException {
        flushBefore(pos);
    }

//    @Override
    public long getFlushedPosition() {
        return flushedPos;
    }

//    @Override
    public boolean isCached() {
        return true;
    }

//    @Override
    public boolean isCachedMemory() {
        return true;
    }

//    @Override
    public boolean isCachedFile() {
        return false;
    }

    private void checkClosed() {
        // nothing to do
    }

//    @Override
    public void mark() {
        markStack.push(new Marker(pos, bitOffset));
    }

    @Override
    public void reset() {
        if (markStack.empty()) {
            return;
        }

        Marker marker = markStack.pop();

        if (marker.bytePos < flushedPos) {
            throw new InternalError("Previous marked position has been discarded!");
        }

        pos=marker.bytePos;
        setBitOffset(marker.bitPos);
    }
}




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